The Northern Harz Boundary Fault (german: Harznordrandstörung or ''Harznordrandverwerfung'') is a
geological fault where the
Harz Block, which consists of rocks formed during the
Palaeozoic Era and folded in the course of
Hercynian mountain building
The Variscan or Hercynian orogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea.
Nomenclature
The name ''Variscan'', comes ...
, borders on the
Subhercynian Basin or
Harz Foreland
The Harz () is a highland area in northern Germany. It has the highest elevations for that region, and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt, and Thuringia. The name ''Harz'' derives from the Middle High German ...
. The fault is also known in English as the Harz North Rim Fault or Harznordrand Thrust (Fault).
[Nielsen, Ole (2008). ''Salt tectonics'' a]
my.opera,com
Accessed on 28 Nov 2010.
The northern edge of the Harz is oriented in a
Hercynian
The Variscan or Hercynian orogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea.
Nomenclature
The name ''Variscan'', come ...
(WNW-ESE) direction and runs from Neuekrug-
Hahausen
Hahausen is a village and a former municipality in the district of Goslar in Lower Saxony, Germany. Since 1 November 2021, it is part of the town Langelsheim, of which it is an ''Ortschaft''.[Langelsheim
Langelsheim is a town in the district of Goslar in Lower Saxony, Germany.
Geography
The municipality is situated between the river Innerste and its tributary Grane, on the northern edge of the Harz mountain range and the Harz National Park, loc ...]
,
Goslar
Goslar (; Eastphalian: ''Goslär'') is a historic town in Lower Saxony, Germany. It is the administrative centre of the district of Goslar and located on the northwestern slopes of the Harz mountain range. The Old Town of Goslar and the Mines ...
,
Bad Harzburg
Bad Harzburg (; Eastphalian: ''Bad Harzborch'') is a spa town in central Germany, in the Goslar district of Lower Saxony. It lies on the northern edge of the Harz mountains and is a recognised saltwater spa and climatic health resort.
Geogra ...
,
Ilsenburg
Ilsenburg () is a town in the district of Harz, in Saxony-Anhalt in Germany. It is situated under the north foot of the Harz Mountains, at the entrance to the Ilse valley with its little river, the Ilse, a tributary of the Oker, about six north ...
,
Wernigerode
Wernigerode () is a town in the district of Harz, Saxony-Anhalt, Germany. Until 2007, it was the capital of the district of Wernigerode. Its population was 35,041 in 2012.
Wernigerode is located southwest of Halberstadt, and is picturesquely s ...
,
Blankenburg Blankenburg may refer to:
Places
* Blankenburg am Harz, a German town in the district of Harz, Saxony-Anhalt
* Blankenburg Castle (Harz), the castle in Blankenburg am Harz (see above)
* Bad Blankenburg, a German town in the Saalfeld-Rudolstadt dis ...
,
Thale
Thale () is a town in the Harz district in Saxony-Anhalt in central Germany. Located at the steep northeastern rim of the Harz mountain range, it is known for the scenic Bode Gorge stretching above the town centre.
Geography
The town is situated ...
and
Gernrode
Gernrode () is a historic town and former municipality in the Harz District, in Saxony-Anhalt, Germany. Since 1 January 2014, it has been part of Quedlinburg.[Ballenstedt
Ballenstedt is a town in the Harz district, in the German state of Saxony-Anhalt.
Geography
It is situated at the northern rim of the Harz mountain range, about 10 km (6 mi) southeast of Quedlinburg. The municipal area comprises the vi ...]
.
The Northern Harz Boundary Fault forms the southern border of the Northeast German Basin, a part of the Central European Basin. The Subhercynian Basin, also known as the Harz Foreland, is a small sub-basin of the Northeast German Basin. This intracontinental basin that has been subsided since the
Permian
The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last ...
period was formed from the Hercynian foreland basins and accumulated sediments of the Mesozoic era. The basin was formed by a deformation or bulging of the
Moho. In the Cretaceous the basin was squeezed by
Alpine orogeny which also uplifted the Harz Block.
The Northern Harz Boundary Fault was activated in the
Early Cretaceous and the Harz was uplifted along the line of the
fault. The Harz Block was thrust over the Mesozoic strata of the Subhercynian Basin, steeply tilting its
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...
strata. The most intensive phase of uplift occurred in a period of about 2 million years from the middle of the
Santonian
The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. ...
age to the lower
Campanian
The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...
. The completion of uplift is shown by the fact that the rocks of the
Upper Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', th ...
lie at a much shallower angle than those of the Lower Cretaceous, and that, in some places, they overlap
discordantly. The uplift is still going on today.
Along the western part of the fault, the Harz was lifted by at least 5 to 7 km, which can be estimated from the thickness of the
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...
rocks deposited in the Harz Foreland and
eroded
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is disti ...
Paleozoic rocks. The Harz was partly thrust over the layers of Mesozoic rock to the north. Here, the Mesozoic strata were tilted steeply (70-80 degrees) or even overturned. A good example is at the Langenberg Quarry, but there are also many other outcrops that show the steeply sloping strata. In these strata, rocks of the
Jurassic
The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...
are steeply inclined. Near Blankenburg and Ballenstedt there are rocks lying at steep angles from the
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
, which form the so-called Devil's Wall or ''
Teufelsmauer
The Teufelsmauer (''Devil's Wall'') is a rock formation made of hard sandstones of the Upper Cretaceous in the northern part of the Harz Foreland in central Germany. This wall of rock runs from Blankenburg (Harz) via Weddersleben and Rieder ...
''. They include, ''inter alia'', rocks of Heidelberg Sandstone, a
silicified
In geology, petrifaction or petrification () is the process by which organic material becomes a fossil through the replacement of the original material and the filling of the original pore spaces with minerals. Petrified wood typifies this proce ...
quartz sandstone.
Springs rise along the entire fault system, both those with low quantities of minerals as well as
mineral water
Mineral water is water from a mineral spring that contains various minerals, such as salts and sulfur compounds. Mineral water may usually be still or sparkling (carbonated/effervescent) according to the presence or absence of added gases.
T ...
springs. The mineral waters are used, for example, in Bad Harzburg, by the spa industry.
See also
*
Geology of Germany
References
Sources
*
*
{{coord missing, Lower Saxony
Geology of Germany
Tectonics
Harz
Regions of Lower Saxony